The inventive concepts relate to a mask for an extreme ultraviolet lithography process and a method of fabricating the same. More particularly, the inventive concepts relate to a mask for an extreme ultraviolet lithography process, which includes an absorber layer an oblique sidewall and a phase shift layer having an oblique sidewall, and a method of fabricating the same.
The reduction of the minimum feature of a device has reduced a cost per function and has improved the functionality of the device at the same time, and thus, a semiconductor industry has been steadily developed. The minimum feature of the device had been reduced at a rate of 70% every three years in history of the semiconductor industry, and recently this reduction cycle of the minimum feature of the device has been reduced to two years. In addition, the cost per function has been reduced at a mean rate of 25% to 30% every year. This trend is called ‘Moore's law’. The development of a lithography process technique transferring an image of a smaller size has been the core of a device miniaturization technique corresponding to a semiconductor growth engine continued in accordance with the trend for the last 45 years.
As described above, the lithography process directly affects the miniaturization and the integration density of the semiconductor device. Integrated circuit (IC) chips having the minimum features of 38 nm had been mass-produced in 2008, and IC chips having the minimum features of 30 nm had been mass-produced in 2010.
A lithography process may use extreme ultraviolet (EUV) corresponding to an electromagnetic wave between the x-ray and the ultraviolet to fabricate semiconductor devices having fine features. Semiconductor devices having the minimum features of 20 nm may be fabricated using the EUV light source.
Meanwhile, since the EUV is absorbed in most of materials and air, the EUV lithography process may not use a transmission mask but may use a reflective mask with respect to the EUV having a wavelength band of 13.5 nm.